Apparatus and Method for Rendering an Audio Signal for a Playback to a User

1. An apparatus for rendering an audio signal for a playback to a user, comprising: wherein the apparatus is configured to determine information about an orientation of a head of the user using an optical sensor; wherein the apparatus is configured to determine information about an orientation of the optical sensor in an Earth-fixed coordinate system using an orientation sensor which is arranged in a predetermined positional relationship with respect to the optical sensor; wherein the apparatus is configured to consider the information about the orientation of the optical sensor when determining the information about the orientation of the head by acquiring at least one parameter about the orientation of the head with respect to an Earth-fixed coordinate system, independent from a current orientation of the optical sensor or from the orientation of the apparatus carrying or comprising the optical sensor; wherein the apparatus is configured to perform a spatial rendering of an audio signal in dependence on the information about the orientation of the head of the user.

2. The apparatus according to claim 1 , wherein the apparatus is configured to perform a binaural rendering in dependence on the information about the orientation of the head of the user.

3. The apparatus according to claim 1 , wherein the apparatus comprises the optical sensor, wherein the optical sensor is arranged to track a head of the user.

4. The apparatus according to claim 1 , wherein the apparatus is configured to determine yaw angle information describing an angle between a head front direction of the head of the user and a position of the apparatus; and/or wherein the apparatus is configured to determine a roll angle information describing a roll angle of the head of the user; and/or wherein the apparatus is configured to determine a pitch angle information describing a pitch angle of the head of the user.

5. The apparatus according to claim 1 , wherein the apparatus is configured to determine yaw angle information describing a yaw angle between a head front direction of the head of the user and a position of the apparatus such that the yaw angle information describes an azimuth angle between the head front direction of the head of the user and a direction from the head of the user to the apparatus.

6. The apparatus according to claim 5 , wherein the apparatus is configured to at least partially compensate a deviation between the direction from the head of the user to the apparatus and a direction of an optical axis of the optical sensor.

7. The apparatus according to claim 1 , wherein the apparatus is configured to determine a roll angle information describing a roll angle of the head of the user with respect to a vertical direction or with respect to a head-front direction.

8. The apparatus according to claim 7 , wherein the apparatus is configured to at least partially compensate a roll angle of the apparatus, or of the optical sensor on the basis of the information about the orientation of the optical sensor when determining the roll angle information describing the roll angle of the head of the user.

9. The apparatus according to claim 1 , wherein the apparatus is configured to determine a pitch angle information describing a pitch angle of the head of the user with respect to a horizontal alignment.

10. The apparatus according to claim 9 , wherein the apparatus is configured to at least partially compensate the orientation of the apparatus or of the optical sensor on the basis of the information about the orientation of the optical sensor when determining the pitch angle information of the head of the user.

11. The apparatus according to claim 1 , wherein the apparatus is configured to determine the information about the orientation of the head on the basis of information from sensors arranged within the apparatus or mechanically attached to the apparatus.

12. The apparatus according to claim 1 , wherein the apparatus is configured to determine the information about the orientation of the head on the basis of information from sensors arranged within the apparatus or mechanically attached to the apparatus, and on the basis of one or more additional sensors which are external to the apparatus.

13. The apparatus according to claim 12 , wherein the apparatus is configured to consider information from the external sensors only if it is found that the information about the orientation of the head cannot be acquired reliably on the basis of the information from the optical sensor.

14. The apparatus according to claim 1 , wherein the apparatus is configured to determine an acoustic front direction, which is a projection of a direction from the head to the apparatus into a horizontal plane, and wherein the apparatus is configured to perform the spatial rendering of the audio signal in dependence on the acoustic front direction.

15. The apparatus according to claim 1 , wherein the apparatus is configured to determine an acoustic front direction, which is a direction from the head to the apparatus, and wherein the apparatus is configured to perform the spatial rendering of the audio signal in dependence on the acoustic front direction.

16. The apparatus according to claim 14 , wherein the apparatus is configured to render a center of an audio scene to be in the acoustic front direction.

17. The apparatus according to claim 14 , wherein the apparatus is configured to determine the pitch angle information describing a pitch angle with respect to the acoustic front direction.

18. The apparatus according to claim 1 , wherein the apparatus is configured to keep a center axis of virtual audio environment level with user's head.

19. The apparatus according to claim 1 , wherein the apparatus is configured to leave a difference in height between head of the user and the apparatus unconsidered when determining the information about an orientation of the head.

20. The apparatus according to claim 1 , wherein the apparatus is portable and/or wherein the apparatus is a mobile communication device.

21. The apparatus according to claim 1 , wherein the apparatus is configured to perform a spatial rendering of multiple audio signals which represent audio contributions from a plurality of participants of an audio conference or of an audio/video conference, and/or wherein the apparatus is configured to perform a spatial rendering of a broadcast or content on local storage media, or streamed audio content.

22. The apparatus according to claim 1 , wherein the apparatus is configured to acquire information at which azimuthal position and at which height or elevation an audio content should be rendered, and wherein the apparatus is configured to determine information about an azimuthal position of the apparatus from the user's perspective using information from the optical sensor and the information about the orientation of the optical sensor; and wherein the apparatus is configured to determine a parameter about the orientation of the head with respect to an Earth-fixed coordinate system using the information from the optical sensor and the information about the orientation of the optical sensor; and wherein the apparatus is configured to render the audio content using the information about the azimuthal position and the parameter about the orientation of the head with respect to the Earth-fixed coordinate system.

23. A method for rendering an audio signal for a playback to a user, comprising: determining information about an orientation of a head of the user using an optical sensor; determining information about an orientation of the optical sensor in an Earth-fixed coordinate system using an orientation sensor which is arranged in a predetermined positional relationship with respect to the optical sensor; considering the information about the orientation of the optical sensor when determining the information about the orientation of the head by acquiring at least one parameter about the orientation of the head with respect to an Earth-fixed coordinate system, independent from a current orientation of the optical sensor or from the orientation of the apparatus carrying or comprising the optical sensor; and performing a spatial rendering of an audio signal in dependence on the information about the orientation of the head of the user.

24. A non-transitory digital storage medium having a computer program stored thereon to perform a method for rendering an audio signal for a playback to a user, the method comprising: determining information about an orientation of a head of the user using an optical sensor; determining information about an orientation of the optical sensor in an Earth-fixed coordinate system using an orientation sensor which is arranged in a predetermined positional relationship with respect to the optical sensor; considering the information about the orientation of the optical sensor when determining the information about the orientation of the head by acquiring at least one parameter about the orientation of the head with respect to an Earth-fixed coordinate system, independent from a current orientation of the optical sensor or from the orientation of the apparatus carrying or comprising the optical sensor; performing a spatial rendering of an audio signal in dependence on the information about the orientation of the head of the user, when said computer program is run by a computer.